NEETZoologyBreathing and Exchange of Gases
Match Column I with Column II regarding the mechanism of breathing. Column I Column II A. Contraction of diaphragm 1. Increases volume in dorso-ventral axis B. Contraction of external intercostal muscles 2. Increases volume in antero-posterior axis C. Relaxation of diaphragm 3. Inspiration D. Intrapulmonary pressure less than atmospheric pressure 4. Expiration Choose the correct option from the following:
Options
- AA-1, B-2, C-3, D-4
- BA-2, B-1, C-3, D-4
- CA-2, B-1, C-4, D-3
- DA-1, B-2, C-4, D-3
Correct answer
C. A-2, B-1, C-4, D-3
Step-by-step solution
According to the mechanism of breathing: Contraction of the diaphragm increases the volume of the thoracic chamber in the antero-posterior axis (A-2). Contraction of the external intercostal muscles lifts up the ribs and sternum, causing an increase in the volume of the thoracic chamber in the dorso-ventral axis (B-1). Relaxation of the diaphragm and intercostal muscles reduces the thoracic volume, leading to an increase in intrapulmonary pressure and causing expiration (C-4). Inspiration occurs when the intrapulmo